Spark plug



y 1949. w. E. HUMRICHOUSE EI'AL. 2,470,821

SPARK PLUG Filed Dec. 14, 1945 I 3mm I Wm me C fluMe/cwo we. Dav/s .8 HUME/(HOUSE EM-g My.

Patented May 24, 1949 SPARK PLUG Walter E. Humrichouse and Davis B. Humi'lchouse, Baltimore, Md., assignors of twenty-two and one-half and twenty-two and one- W. Abell, both of Baltim per cent to Walter H. Smith, Sr., hall. per centto George ore, Md.

Application December 14, 1945, Serial No. 634,929

. Claims.

This invention relates to internal combustion equipment and more particularly to spark plugs therefore.

The art of spark plugs is highly developed and is generally well known. The general disadvantages oi the existing types are that they are selffouling; have a tendency to get as hot as the engine and be subject to relatively high temperatures. They also are limited in spark value, that is the spark gap is such that but one short spark is developed in its use and its power to start the combustion of the mixed gases within the firing chamber of the engine made relatively small. These spark plugs offer no method of showing what is actually occurring .with regard to the sparks, that is, whether they are good, bad or indifferent, and therefore afiord no means for checking their values. The usual way to check up on the spark plugs is take the spark plug and try it on a special piece of equipment. Another way is to short circuit the plug while the engine is running and determine from the resultant response of the engine whether the spark is good or not. Another way is to use a helium flask and judge from the resultant spark within it whether the plug is acting properly or not. All of these methods are indirect and require special tools while using up time. Their great objection however from the drivers point of view is in the fact that they usually cause the soiling of his hands and clothes. The electrodes used with the conventional plugs have a relatively large chamber that serves as a reservoir for the collection of car; bon and contamination of the surfaces of the plugs where short circuiting is liable to result.

It is an object of the present invention to provide a new and improved spark plug that will avoid one or more of the disadvantages and limitations of the prior art. Y

Another object of the invention is to provide a new and improved spark plug that will be selfcooling and air circulating interiorly and exteriorly.

A further object of this invention is to provide a new and improved spark plug that will provide sparking on a considerable area and igniting power without oilering opportunities for carbonizing or fouling of the electrodes. Still another object of the present invention is to provide a new and improved spark plug that will give a clear visual indication of its behavior during operation.

An additional object of the invention is to provide a new and improved spark plug, that will be 2 positively non-fouling, and self-intensifying in effect during operation.

In order to give a clearer understanding of the invention and for other objects thereof reference is made to appended drawings and following description of the selected example used to illustrate it herein, while the scope of the invention is particularly pointed out in the claims.

Figure 1 is a side elevation of a spark plug em-- bodying this invention;

Figure 2 is a sectional view taken along line 2-2 of Figure 1;

Figure 3 is a sectional view taken along line 3-3 of Figure 2, and

Figure 4 is the spark plug in a modified form.

Similar reference characters refer to similar parts throughout the drawings.

Referring particularly to Figure 2, wherein the parts of the spark plug of this invention, are illustrated, a metal shell ll having an externally threaded lower bodyl! for attaching it within the screw-threaded spark-plug opening in an internal combustion engine l3, while a hexagonrial, and form a tight joint.

shaped tool portion I4 is adapted for fastening it with a wrench in place, in a conventional manner. The middle portion I5 is cylindrical and is enlarged so as to rest on the engine head when the shell is screwed into place. The shell is formed with a series of squared stepped fins l6 spaced apart longitudinally along the upper portion of the shell. Internally the shell is hollow but is formed with an orifice I! tapered inwardly to hold the tapered end of an electrode spindle insulator l8 of glass or other suitable mate .The hollow portion of the shell has two chambers l9 and 2!. The walls of the chamber l9 belong to the portion l2 and are spaced away from the insulator Hi to provide air space and cooling arrangement around the latter. The chamber 2| has its walls internally screw threaded throughout to provide for the adjustment of a cylindrical externally screw-threaded block 22 therein in a longitudinal direction. This block is employed to hold the spindle insulator iii in position in the spark plug by impressing itself against its enlarged circular shoulder 23 and holding it down against the tapered orifice I! at the bottom of the chamber l9. Slots 20 are cut longitudinally in the block'for ventilating purposes, and may be used to hold. a wrench for adjusting it. The chamber 2| is ventilated through passages 25 passing from the peripheral surfaces of the portion H to the inside, and also with passages 26" entering peripherally near the top of the shell I I.

The top rim 21 of the shell is bent over to hold a transparent and insulating bell-shaped hollow dome 28, the bottom. portion 29 of which is enlarged to provide a flange on which to form the rim 2'! to tightly encompass it. The upper end portion of the dome 28 is drilled through to provide a passage 3| leading to the chamber 32 within it. This passage contains an electrode 33 which forms a connection to the circuit in which the spark plug is coupled. It is threaded externally for the purpose and has the hexagon nuts adjustable thereon for holding the wire to such circuit. The electrode 33 fits closely in the passage and the copper washer 34 assists in giving it a tight connection. The electrode has a disc 35 integrally attached to it and located within the chamber 32. This disc forms an intensifying area for the accumulation and discharge capacity during the operation of the spark plug. It also serves to tighten the electrode to the dome 28 when the nuts are screwed into place. The spindle insulator l8 extends into the chamber 32 but is spaced from the walls thereof, and it also has a peripheral groove 36 near the exposed end where the rounded head 38 of the other electrode 39 extends to make the initial space for the spark gap of the plug. The electrode 39 extends longitudinally through the passage ll in the spindle insulator and terminates within the chamber 32 with a screw threaded portion on which a screw threaded disc 42 is attached to hold it tightly in the insulator I8. This disc 42 is similar to the disc 35 and is brought close enough to provide sufficient space for a sparking between them and forming a condenser eflect. The sparking can be seen through the transparent walls of the dome 28 when in operation.

A conducting ring 43 sets in the groove 36 and is spaced from the electrode head 38 a predeterminded sparking distance, as is also the ring from the conducting and grounded body I2 of the shell. To facilitate the sparking action, sparking points 44 and 45 are mounted on the head 38 and shell l2 respectively as indicated.

In the operation of the spark; plug the circuit supplies electrical energy to the electrode 33. This energy jumps the adjusted space between the intensifying discs 35 and 42 and passes down through the electrode 39 .and its head 38. It

jumps or sparks between the head 38 from its point 44 to the ring 43, and from the latter to the point 45. This produces a double gap which provides double ignition for the explosive gases within the engine. As a matter of practical effect, the sparks actually jump across at many points around the head, ring and end of the shell so that a very substantial ignition effect is provided. This sparking being externally to the plug gives it much closer contact within the gases and thereby more effective ignition, and avoids fouling as all the extrodes are exposed at the ignition areas. The passages 25 and 26 within the shell and dome ofi'er ingress and egress of air to the chambers l9, 2! and 32 to cool off the external and internal surfaces it contacts with. The fins l6 also facilitate the removal of heat from the shell. This reduces the stresses considerably on the parts of the spark plugs and gives it longer wearing qualities. The transparent dome, which is preferably made of a Pyrex glass allows the sparking to be seen through it, and the operation of each plug evaluated. This sparking also offers appreciable value as an illuminant for the space under the hood at night, especially when all cylinders of the engine are firing. The intensifying insulator ofiers very little area against which the shell or dome can compress it during its varying temperature responses.

In the modification shown in Figure 4 the additional and spaced points 48 provide a longer path and more sparks in various channels for ignition purposes in the cylinder of the engine with its consequent increase in effectiveness.

While but two general forms of the invention are shown in the drawings and described in the specification, it is not desired to limit this application for patent to this particular form or in any other way otherwise than limited by the scope thereof, as it is appreciated that other forms could be made that would use the same principles and come within the scope of the appended claims.

Having thus described the invention, what is claimed is:

1. A spark plug comprising a shell adapted for attachment to gas explosion equipment, said shell having a tapered orifice, a hollow spindle insulator disposed in said shell and having a portion tapered to fit tightly in said orifice when said portion is projected thereinto, an electrode disposed in said hollow portion of said spindle insulator and f tting closely therein, said electrode having a head thereon contacting closely against the projecting portion of the insulator so as to tightly close the hollow portion thereof, and including another portion with an attachment thereon for fastening the positioned electrode to the insulator, adjustable means for holding said insulator to the shell but spaced at various portions from the wall thereof to provide for air circulation on the internal surfaces of the shell of the insulator, a dome fastened to the shell having a chamber therein for said insulator and electrode to project into and be spaced from the walls thereof, another electrode mounted on the dome and projecting into the chamber thereof but spaced from the first mentioned electrode predeterminedly to provide an intensified electrical coupling therebetween, said head being so placed in regard to the shell as to provide for plural sparking in between same external to the shell and electrode when operated by electrical energy.

2. A spark plug comprising a cylindrical conducting shell adapted for conventional attachment togas explosion equipment, said shell having a tapered orifice at one end thereof, a hollow spindle insulator disposed in said shell and having a portion externally tapered to fit tightly in said orifice when said portion is projected thereinto, an electrode disposed in said hollow portion of said spindle insulator and fitting closely therein, said electrode having a rounded head thereon contacting closely against the projecting portion of the insulator so as to tightly close the hollow portion thereof, and be disposed entirely outside said insulator and including another portion with an attachment thereon for fastenin the externally positioned electrode to the insulator, adjustable means for holding said insulator to the shell but spaced at various portions from the wall thereof to provide for air circulation on the internal surfaces of the shell of the insulator, a transparent insulating dome fastened to the shell having a chamber therein for said insulator and electrode to project into and be spaced from the walls thereof, another electrode mounted on the dome and projecting into the chamber thereof but spaced from the first mentioned electrode predeterminedly to provide an intensified electrical coupling therebetween, said head being so placed in regard to the shell as to provide for plural sparking in between same external to the shell and electrode when operated by electrical energy, and means for providing an arcuate path for the energy to travel over in between said shell and electrode, said transparent dome aifording a visualizing of the intensified action between the electrodes within the dome during said operation.

3. A spark plu comprising a cylindrical conducting shell adapted for conventional attachment to gas explosion equipment, said shell having a tapered orifice at one end thereof, a hollow spindle insulator disposed in said shell and having a portion externally tapered to fit tightly in said orifice when said portion is projected thereinto, an electrode disposed in said hollow portion of said spindle insulator and fitting closely therein, said electrode having a rounded head thereon contacting closely against the projecting portion of the insulator so as to tightly close the Hollow portion thereof, and be disposed entirely outside said insulator and including another portion with an attachment thereof for fastening the externally positioned electrode to the insulator, adjustable means for holding said insulator to the shell but spaced at various portions from the wall thereof to provide for air circulation on the internal surfaces of the shell of the insulator, a transparent insulatin dome fastened to the shell having a chamber therein for said insulator and electrode to project into and be spaced from the walls thereof, another electrode mounted on the dome and projecting into the chamber thereof but spaced from the first mentioned electrode predeterminedly to provide an intensified electrical coupling therebetween, said head being so placed in regard to the shell as to provide for plural sparking in between same external to the shell and electrode when operated by electrical energy, means for providing an arcuate path for the energy to travel over in between said shell and electrode, said transparent dome affording a visualizing of the intensified action between the electrodes within the dome during said operation, and means for facilitating the air circulation in the dome and shell and exteriorly thereto for cooling same.

4. A spark plu comprising a shell adapted for attachment to gas explosion equipment, said shell having a tapered orifice, a hollow spindle insulator disposed in said shell and having a portion tapered to fit tightly in said orifice when said portion is projected thereinto, an electrode disposed in said hollow portion of said spindle insulator and fitting closely therein, said electrode having a head thereon contacting closely against the projecting portion of the insulator so as to tightly close the hollow portion thereof, and including another portion with an attachment thereon for fastening the positioned electrode to the insulator, adjustable means for holding said insulator to the shell but spaced at varions portions from the wall thereof to provide for air circulation on the internal surfaces of the shell of the insulator, a dome fastened to the shell having a chamber therein for said insulator and electrode to project into and be spaced from the walls thereof, another electrode mounted on the dome and projectin into the chamber thereof but spaced from the first mentioned electrode predeterminedly to provide an intensified electrical coupling therebetween, said head being 'so placed in regard to the shell as to provide for plural sparking in between same external to the shell and electrode when operated by electrical energy, and a ring mounted on the spindle insulator for providing an intervening conducting path between said head and shell and introducing a plural spark gap in between and across the insulator external to the shell.

5. A spark plug comprising a shell adapted for attachment to gas explosion equipment, said shell havin a tapered orifice, a hollow spindle insulator disposed in said shell and having a portion tapered to fit tightly in said orifice when said portion is projected thereinto, an electrode disposed in said hollow portion of said spindle insulator and fitting closely therein, said electrode having a head thereon contacting closely against the projecting portion of the insulator so as to tightly close the hollow portion thereof, and including another portion with an attachment thereon for fastening the positioned electrode to the insulator, adjustable means for holding said insulator to the shell but spaced at various portions from the wall thereof to provide for air circulation on the internal surfaces of the shell of the insulator, a dome fastened to the shell having a chamber therein for said insulator and electrode to project into and be spaced from the walls thereof, another electrode mounted on the dome and projecting into the chamber thereof but spaced from the first mentioned electrode predeterminedly to provide an intensified electrical coupling therebetween, said head being so placed in regard to the shell as to provide for plural sparking in between same external to the shell and electrode when operated by electrical energy, conductor means mounted on the spindle insulator for providing an intervening conducting path between said head and shell and introducing a plural spark gap in between and across the insulator external to the shell, said shell having its wall perforated to connect the passages into chamber and dome for the ingress and egress of air therethrough.

WALTER E. HUMRICHQUSE. DAVIS B. HUMRICHOUSE.

REFERENCES CITED The following references are of record in the 

